I was about to edit the localization tag. Then I realized that there is no internationalization tag. However, there is a wrongly created l18n (should be l10n) tag as a tag synonym for localization, even though the correct synonym l10n exists separately. Also, i18n is set as another synonym for localization, although internationalization is a separate topic.

There is also a translation tag which essentially has questions that are either related to localization or internationalization. Not to mention, there are separate tags for textdomain, language, po and mo, phew!

Finally, there is a separate multi-language tag, which is rightly separate from the other tags I've mentioned above, although most of the questions there are not related to multi-language, but related to either internationalization or localization (i.e. translation).

I don't have the privileges to fix all that, and if I edit / alter all of these tag wiki, those who will approve it may become confused without proper context. That's the reason why I'm writing this question.

Now my question is: what should be the correct combination of tags related to translation?

I like the idea of two tags only, but I would opt for textdomain in stead of translation.

The reason for this is that more serious developers, whom I see as our core users, will use textdomain to describe the development issue they are addressing. translation is a colloquial synonym, but not the correct WP term.

You can have translation problems where the text domain is not an issue at all, date i18n for example.
– fuxia♦Mar 24 '17 at 10:40

According to WP translation handbooklocalization, internationalization, textdomain etc. all are part of the greater term translation. It's not only a well understood term among developers & English speaking people, it's well understood for non-English speaking people as well. Just think about it, the first word you'll ever learn if you are interested in translation is translation ;)
– FayazMar 24 '17 at 11:22

Also, AFAIK, people will still be able to tag and search by those synonyms, only system will properly merge them into one place. Not to mention that the total number of posts with all those tags combined suggests we can just have two.
– FayazMar 24 '17 at 11:22

I've updated the number of posts against each separate tags in the question, this should make further discussion easier.
– FayazMar 24 '17 at 11:34

For me, out of the list of terms given, the ones that should not be there are translation, language, l10n, po and mo. translation is the process of producing text in different language which wordpress has nothing to do with, the rest are just not meaningful.

textdomain is a technical term used as part of localization so it should stay, localization obviously should stay, and multi language (should be multi locale but lol no one will use or understand it) is a way to set wordpress for multiple localizations.

BTW i18n for me is not a useful term, in many countries you need to handle two or more languages just for the country itself, calling it a i18n is a little be of stretch. So maybe i18n should be a synonym of localization.

I agree that terms such as po, mo are useless. However, not having them as synonym means new uses will add them to the system again! Also, WP core heavily uses the terminology translation, which is further divided into two parts: internationalization (i18n) & localization (l10n). So even though these terms are generic & often used interchangeably, having them as tags and synonyms are useful. The challenge is to determine which should be the main tag and which should go to synonym.
– FayazApr 5 '17 at 10:25

agree on the use of whatever synonyms as needed. As for translation, the process is indeed translation, but that is orthogonal to development. Unless wordpress is integrating with something like google translate, there is very little software in core which is related to translating..... maybe use translation API to relate to the __ and _e function might be a good alternative. i18n is the assistance of the __ API at all, and not related much to plugin/theme development, except in a very high level way.
– Mark KaplunApr 5 '17 at 10:35

As for codex people not knowing official meaning of english words, it is refreshing to complain about something else than the quality of the examples in the codex ;)
– Mark KaplunApr 5 '17 at 10:36